I. Field of the Invention
The present invention relates generally to accessory gauges for measuring angles. More particularly, the present invention relates to a portable, angle measuring gauge that may be quickly retrofitted to material bending apparatus including sheet metal brakes and the like. Known prior art devices are found in United States Patent Class 33, Subclass 534.
II. Description of the Prior Art
In many manufacturing operations, it is necessary to check the angular relationship of one part with respect to another part. For example, in home restoration and building applications it is desirable to bend aluminum siding or sheet metal. Several sheets of material must be custom bent to finish the job. The bend angle created in these several sheets must be uniform for a correct fit. While measuring instruments have been devised for the measurement of angles, such instruments are quite complicated and very specialized in that they are constructed for the measurement of angles under particular circumstances.
U.S. Pat. No. 5,375,340 describes a device for measuring the bend angle of a metal sheet in a press brake. This is achieved by using a small disk mounted on a support. The disk is capable of rotating over a limited angle. The rotation of the disk is detected by a device that calculates the bend angle based on the disk's movement. One problem associated with a measuring device of this type is that it is part of the press. Another problem is that a complex detection means are required to provide the measuring signals to enable the device to calculate the bend angle. Yet another problem is that a measuring device of this type is not portable.
Other prior art devices for monitoring the bend angle are adapted to fit sheet bending presses that attach to press without requiring a special die. These devices detect a bending angle using a sensor mounted to a back stop. The sensor is connected electronically to the press. Signals from the sensor are sent to a control mechanism on the press to control the angle formed. A problem with devices of this type is that the require complex electronic circuits to control the press. A further problem associated with devices of this type is that they are not able to produce a limited number bends containing unique angles without costly reprogramming. Another problem is that these devices are not easily moved from one job site to another.
For example, when installing aluminum siding it is often necessary to adapt several pieces of siding to conform to a unique structure encountered during the course of the job. Portable bending devices are used to shape the siding in the field. These portable benders are hand operated press brakes in which an operator uses a lever to apply the pressure that bends the siding. The operator must rely on the "feel" of the press or mearly view the bend as it takes place to try and create several pieces with a uniform bend angle. This results in pieces with angles that are not precise and as such do not fit correctly. These pieces are discarded and new bends attempted. This results in increased time and cost to complete the job.
Thus, it is desirable to have a portable retrofitting device for accurately measuring the angular displacement of a moveable machine part.